28891439 has 4 divisors (see below), whose sum is σ = 28906080. Its totient is φ = 28876800.

The previous prime is 28891433. The next prime is 28891451. The reversal of 28891439 is 93419882.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 28891439 - 2¹⁶ = 28825903 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28891439.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28891433) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3794 + ... + 8495.

It is an arithmetic number, because the mean of its divisors is an integer number (7226520).

Almost surely, 2^28891439 is an apocalyptic number.

28891439 is a deficient number, since it is larger than the sum of its proper divisors (14641).

28891439 is a wasteful number, since it uses less digits than its factorization.

28891439 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14640.

The product of its digits is 124416, while the sum is 44.

The square root of 28891439 is about 5375.0757203969. The cubic root of 28891439 is about 306.8478310200.

The spelling of 28891439 in words is "twenty-eight million, eight hundred ninety-one thousand, four hundred thirty-nine".